Fig. 2.

Crystal structure of androgen receptor ligand binding domain in complex with dihydrotestosterone (DHT). The chemical structure of DHT is shown on right side. Binding of agonistic ligands to the AR results in the agonist conformation of helix 12 (shown in magenta) which allows the co-activator binding at the AF-2 region indicated by dotted circle. Chemical modification at the 11-position of steroidal ring results in the displacement of helix 12 from its agonistic conformation and allow the sidechain at 11-position to be exposed to solvent. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]